Plimpton 322
Plimpton 322 is a Babylonian clay tablet, believed to have been written around 1800 BC, that contains a mathematical table written in cuneiform script. Each row of the table relates to a Pythagorean triple, that is, a triple of integers ( s , l , d ) {\displaystyle (s,l,d)} that satisfies the Pythagorean theorem, s 2 + l 2 = d 2 {\displaystyle s^{2}+l^{2}=d^{2}} , the rule that equates the sum of the squares of the legs of a right triangle to the square of the hypotenuse.